These notes contain all the AO1 and AO3 needed for the biopsychology module of AQA A level psychology paper 2. The information is split up into AO1, meaning the knowledge points the specification looks for, and AO3, wherein each point is a strength or a weakness related to the provided knowledge. T...
Biopsychology
The nervous system
♡ specialised network of cells in the human body
♡ based on electrical and chemical signals
♡ 2 main functions:
- Collect, process, and respond to information in the environment
- Coordinate the working of different organs and cells in the body
CENTRAL NERVOUS SYSTEM (CNS)
♡ made up of brain and spinal cord
♡ the brain is the centre of conscious awareness
♡ the cerebral cortex covers the brain- it is highly developed in humans and
distinguishes our higher mental functions
♡ the spinal cord passes messages to and from the brain and connects nerves to the PNS
♡ responsible for reflex actions
PERIPHERAL NERVOUS SYSTEM (PNS)
♡ transmits messages via neurons to and from the CNS
♡ autonomic nervous system (ANS) governs vital functions such as breathing, heart rate,
digestion, and stress responses
- Sympathetic controls flight or fight response
- Parasympathetic is our usual resting system
♡ somatic nervous system (SNS) governs muscle movement and receives information
from sensory receptors
The endocrine system
♡ acts more slowly but has widespread powerful effects
♡ glands produce hormones which are secreted into the bloodstream and affect any cell
that has a receptor for that particular hormone
♡ affect cells in more than 1 organ for diverse responses
♡ thyroid gland produces the hormone thyroxine
- increases heart rate
- increase metabolic rates
- Affects growth rates
♡ endocrine gland located in the brain- controls the release of hormones from other
endocrine glands
♡ endocrine system and ANS work together in fight or flight responses during a stressful
event
♡ when a stressor is perceived, the hypothalamus activates the pituitary gland
♡ ANS changes from its normal resting state (parasympathetic) to the physiologically
aroused sympathetic stage
♡ the hormone adrenaline is released from the adrenal medulla
♡ adrenaline triggers changes e.g., increased heart rate which creates physiological
alertness needed for fight or flight
♡ the changes caused are…
, - Increased heart rate
- Increased breathing rate
- Pupils dilated
- Digestion inhibited
♡ when the threat has passed, the parasympathetic branch reverses these changes
Neurons
♡ sensory carry messages from the PNS to the CNS, and have long dendrites and short
axons
♡ relay neurons connect the sensory and motor neurons, and have short dendrites and
axons
♡ motor neurons connect the CNS to effectors such as muscles, and have short dendrites
and long axons
♡ the cell body (soma) has a nucleus, which includes the genetic material of the cell
♡ branch like structures called dendrites protrude from the cell body, and carry nerve
impulses from neighbouring neurons towards the cell body
♡ axon carries impulses away from the cell body down the length of the neuron
♡ a fatty layer of myelin sheath protects the axon and speeds up electrical transmission
♡ myelin sheath segmented by gaps called nodes of Ranvier, speed up transmission by
forcing the impulse to ‘jump’ across gaps
♡ terminal buttons communicate with the next neuron in the chain across a gap called
the synapse
♡ sensory neurons are in the PNS in clusters called ganglia
♡ when a neuron is resting the inside of the cell is negatively charged compared to the
outside
♡ when activated by a stimulus, the inside becomes positively charged, causing an
action potential to occur
♡ this creates the electrical impulse which travels down the axon to then end of the
neuron
Synaptic transmission
♡ neurons communicate in groups called neural networks
♡ each neuron is separated by a gap called the synapse
♡ within neurons, messages are communicated electrically, between neurons they are
communicated chemically
♡ when the electrical impulse reaches the presynaptic terminal it triggers the release of
neurotransmitters (NT) from sacs called synaptic vesicles
♡ NTs are chemicals that diffuse across the synapse to the next neuron in the chain
♡ NT taken up by a postsynaptic receptor site on the dendrites of the next neuron
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